Tin Powder Research Articles

Superior Iodine Uptake Capacity Enabled by an Open Metal-Sulfide Framework Composed of Three Types of Active Sites

Superior Iodine Uptake Capacity Enabled by an Open Metal-Sulfide Framework Composed of Three Types of Active Sites

Searching New Solutions for NiTi Sensors through Indirect Additive Manufacturing.

Shape Memory Alloys (SMAs) can play an essential role in developing novel active sensors for self-healing, including aeronautical systems. However, the NiTi SMAs available in the market are almost limited to wires, small sheets, and coatings. This restriction is mainly due to the difficulty in processing NiTi through conventional processes. Thus, the objective of this study is to evaluate the potential of one of the most promising routes for NiTi additive manufacturing—material extrusion (MEX). Optimizing the different steps during processing is mandatory to avoid brittle secondary phases formation, such as Ni3Ti. The prime NiTi powder is prealloyed, but it also contains NiTi2 and Ni as secondary phases. The present study highlights the role of Ni and NiTi2, with the later having a melting temperature (Tm = 984 °C) lower than the NiTi sintering temperature, thus allowing a welcome liquid phase sintering (LPS). Nevertheless, the reaction of the liquid phase with the Ni phase could contribute to the formation of brittle intermetallic compounds, particularly around NiTi and NiTi2 phases, affecting the final structural properties of the 3D object. The addition of TiH2 to the virgin prealloyed NiTi powder was also studied and revealed the non-formation of Ni3Ti for a specific composition. The balancing addition of extra Ni revealed priority in the Ni3Ti appearance, emphasizing the role of Ni. Feedstocks extruded (filaments) and green strands (layers), before and after debinding & sintering, were used as homothetic of 3D objects for evaluation of defects (microtomography), microstructures, and mechanical properties. The composition of prealloyed powder with 5 wt.% TiH2 addition after sintering showed a homogeneous matrix with the NiTi2 second phase uniformly dispersed.

Effect of milling energy on phase transformation of Ti-Ni powders during mechanical alloying

ABSTRACT The effect of milling energy on the phase evolution of mechanically alloyed Ti–Ni powders is reported. Alloys were produced by low-energy and high-energy mechanical alloying (LEMA and HEMA, respectively). Powders milled for different times were characterised by X-ray diffraction and scanning electron microscopy. The phase transformations of powders milled by LEMA and HEMA before amorphisation are presented. During LEMA, TiNi, TiNi3, Ti3Ni4, and Ti2Ni were formed at 50 and 100 h. At these times, the results were consistent with the Ti–Ni equilibrium phase diagram. Up to 7.27 wt% of TiNi with a crystallite size of 32.63 ± 0.01 nm appeared at 50–75 h. During HEMA, iron contamination inhibited the formation of the TiNi phase at short milling times, and up to 47.9% of Fe0.2Ni4.8Ti5 was generated. These results indicate that amorphisation and heat treatment are not the only methods of promoting phase transformation in Ti–Ni alloys.

Mechanical and Tribological Performance of Polypropylene/Tin Powder Composites

In this study, the effect of Tin powder filler content on the mechanical and tribological performance of Tin filled Polypropylene (PP) composites were investigated. Polypropylene composites were prepared in a Brabender kneading chamber. The melt was transferred to a laboratory hot press and compression molded into samples for tests. The mechanical performances of the polymer based composites were determined by tensile and notched izod impact tests. The tribological tests were carried out in dry condition using pin-on-disc at 0.5−1.5 m/s Sliding Speed (SS) and 10–30 N loads. The mechanical test results demonstrated that the incorporation of Tin powders increased the Tensile Strength (TS) (5.6%), tensile modulus (TM) (19.8%) and izod Impact Strength (IS) (41.8%) while decreased the Elongation at Break (EB) (80%) values of Tin powder filled PP composites. The Friction Coefficient (COF) and Specific Wear Rate (SWR) decreased with the increase in filler content. The COF of unfilled PP, PP-8% Tin powder, PP-16% Tin powder and PP-24% Tin powder composites decreased about 20%, 23.4%, 21.8% and 29.3% with the increase in applied load from 10 N to 30 N, respectively. The SWR of the Tin powder filled PP composites decreased by 91% compared to unfilled PP polymer at 1.5 m/s speed and 30 N load value.

Enhancing mechanical properties of Ti(C, N)-based cermets via preparation with (Ti, W)(C, N) multi-component powder

Using the traditional preparation method of TiC+TiN powder mixture or simply the Ti(C, N) solid-solution powder to prepare cermet cannot properly avoid the direct contact between TiC, TiN or Ti(C, N) phase and (CoNi) binder phase with undesirable wettability, which is disadvantageous to the strength and toughness of cermet. Here, we introduced a new routine using the (Ti, W)(C, N) solid-solution powder and studied the resultant phase constitutions, microstructures and properties of the Ti(C, N)-based cermets, where the cermets prepared with TiC + TiN + WC and Ti(C, N) + WC were taken as counterparts. The X-ray diffraction (XRD) results showed that regardless of the powder combination, two phases, i.e. fcc-(Ti, M)(C, N) and fcc-(CoNi), were formed, and the lattice constants of these phases varied in different samples, which is attributed to the specific phase stability (TiN > Ti(C, N) > (Ti, W)(C, N) > TiC) calculated based on the CALPHAD (CALculation of PHAse Diagrams) approach. Transmission electron microscopic (TEM) observations further depicted that besides the already-known core-rim structure, the cermet prepared using (Ti, W)(C, N) uniquely incorporated black-gray rimless grains and black-white-gray rimless grains. Two critical mechanical properties, i.e. hardness (H) and fracture toughness (KIC), were subsequently determined using the Vickers indentation method. It was found that the KIC values of the cermet prepared using (Ti, M)(C, N) were improved by 5.1% ~ 29.2% while maintaining the similar level of H as other cermet samples. The segregation of W and Ti in (Ti, W)(C, N) powders led to the formation of cleavage facets in ceramic grains, which could contribute to the hinderance of crack propagation. Eventually, the high-temperature (750 °C) wear tests were conducted to examine the durability of cermet samples. The cermet prepared using (Ti, M)(C, N) generally exhibited enhanced wear resistance, benefiting from the well-balanced H and KIC as well as the restraint of oxidational wear. Thus, this work suggested that preference should be given to (Ti, W)(C, N) solid-solution powders when fabricating high-performance Ti(C, N)-based cermets.

A titanium-nitrogen alloy with ultrahigh strength by ball milling and spark plasma sintering

The high strength and low cost of titanium alloys have led to the development of these alloys for aerospace applications. In this study, ultra-high-strength Ti–N alloys were fabricated by ball-milling (BM) and spark plasma sintering (SPS), and the effects of the nitrogen content on the microstructure and mechanical properties of the alloys were studied. TiN powder was used as the raw material for doping the alloys with N atoms, and the N content was controlled by tuning the amount of TiN powder added. The yield strength of the Ti–N alloys increased with an increase in the N content and surpassed 2000 MPa when the N content reached 2.66 wt%. Quantitative analysis using the Hall-Petch equation and Labusch model demonstrated that fine-grain strengthening and solution strengthening worked in synergy to enhance the strength of the Ti–N alloys. The ultra-high-strength Ti–N alloys can be applied in the aerospace field for structure use, such as aircraft engines, fasteners, and burn-resistant materials. The preparation of novel Ti–N alloys validates the theoretical application of ubiquitous elements in titanium alloys.

A Co-operative Synthesis Approach to Prepare Tin Oxide Thin Films by Thermal Evaporation, Muffle Furnace Technique and Its Glucose Sensing Applications

Tin Oxide/Dioxide material plays an important role in many applications such as solar cell, sensors, optical devices and electronic devices. Tin oxide/dioxide films were thermally grown on glass substrates by the thermal method of pure metallic tin powder on glass substrates with 100nm thickness at 300oC substrate temperature for glucose sensing. An aluminium electrode was used as the contact on top of the thin films. It was used to detect the various glucose concentrations (50,100,150,200, 250 & 300) mg/dL at room temperature. The films were annealed at different temperatures and investigated for oxidation, physical and structural properties. The surface properties were studied by scanning electron microscopy and atomic force microscopy. Different elements of oxide films were recorded by energy dispersive X-ray (EDAX). For structural analysis, X-ray diffraction measurements were carried out and electrochemical workstation was used to analyse the glucose (C6H12O6) sensing. It was found to be the SnO2 film at 500oC temperature shows a better response than the other films and this was obtained as a biomedical sensor. Keywords: Tin oxide, Muffle furnace, Thermal evaporation, Glucose sensor.

Increasing hydrogen sorption by ti2ni powder using mechanochemical alloying

A method has been developed to increase hydrogen sorption by Ti2Ni powder, which consists in mechanochemical alloying by titanium of Ti-Ni powder near the equiatomic composition. This method allows the hydrogen content in the powder material to be increased several times. It is possible to use the developed powder material for the safe storage and transportation of hydrogen in the metal hydride with a high hydrogen content, with reversible adsorption of hydrogen, in comparison with the storage and transportation of hydrogen in compressed and liquid form. The developed method is simple to implement and low-cost; therefore, it is of economic and practical interest. For mechanochemical alloying, a high-intensity planetary ball mill was used, with a drum rotation speed of 1820 rpm and a processing time of 300 seconds. It is shown that, after mechanochemical alloying, the powder Ti-Ni (85 wt%) – Ti (15 wt%) powder consisted of TiNi in two modifications, namely B2 and B19`, and two Ti2Ni phases with different lattice parameters. The existence of two Ti2Ni phases is due to both the inheritance of this phase from the initial Ti-Ni powder (Ti2Ni(I)), and its formation during the interaction of titanium with TiNi (B2, B19`) in the process of mechanochemical alloying (Ti2Ni(II)). The Ti2Ni (II) phase formed by mechanochemical alloying is more prone to interact with hydrogen with the formation of Ti2NiHx hydride than the Ti2Ni (I) phase present in Ti-Ni powder before alloying. The lattice parameter of the Ti2Ni (II) phase increases by 17.6 % during hydrogenation and corresponds to Ti2NiH2.8 hydride; this result exceeds the change in the cell volume of Ti2Ni obtained by other methods.

Change in electronic state of nitrogen in oxidized titanium nitride

The changes in the electronic state and local structure of nitrogen in TiN powders heated in air were investigated by X-ray diffraction, diffuse reflectance, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near-edge-structure (XANES) measurements. The oxidation of TiN powder accompanied by desorption of nitrogen started from the surface of the powder particle, resulting in a transformation from TiN to TiO2 with increasing heating temperature. The diffuse reflectance spectra showed the formation of nitrogen-doped TiO2 with an absorption band at 2.9 eV by heating TiN powder above 600 °C. XPS measurement revealed the presence of nitrogen with a negative charge in TiN powders and with a neutral or positive charge in highly-oxidized powders containing a small amount of nitrogen. XANES measurement for nitrogen clarified the presence of nitrogen bound to oxygen which form some complex species such as NO molecule in the powders oxidized above 400 °C.

The effect of sodium (Na) doping on the performance of n-Si/Cu2SnS3 heterojunction solar cells deposited by PLD using a homemade target.

n-Si/Cu2SnS3(CTS) heterojunction solar cell has been fabricated in this work using different doping concentration of Na into CTS thin films. The pure raw powders of Copper, Tin, Sulphur and NaF have been ball milled, pressed and heated to form CTS pure and Na doped targets. The deposition of CTS thin film pure beside 1%, 3% and 5% Na doped CTS thin film have been held by pulsed laser deposition technique. The different properties of CTS thin films have been studied using different analyse methods and it has been observed that the properties of these CTS thin films are strongly dependent on Na concentration. Doping CTS thin films with 1% Na has enhanced the crystallinity and the optical absorption. The solar cells based on n-Si/p-CTS heterojunction present different power conversion efficiency according to Na concentration in CTS thin films. The best photovoltaic performance has been obtainable by Al/n-Si/CTS(1%Na doped)/Ag solar cell with open circuit voltage of 300 mV and power conversion efficiency of 1.02%.

Growth and characterization of GeSnO thin films for thermoelectric power generation applications

In this paper, we have demonstrated the thermoelectric properties of GeSnO thin films grown by physical vapor deposition technique. The GeSn pellets were prepared by mixing of germanium (Ge) and tin (Sn) powders with 1:1 ratio using a hydraulic press. Hard pellet was evaporated in a vacuum tube furnace on glass substrate. The grown sample was cut into pieces and subjected to the annealing process at different temperatures ranging from 350 to 500 0C in an oxygen environment. XRD data confirmed the formation of GeSnO crystal structure and it was found to be improved up to annealing temperature 350 °C due to the compensation of oxygen vacancy type defects. But further annealing temperature degrades the crystal quality because oxygen atoms get additional thermal energy and it may generate interstitial defects. Raman and SEM data further supported our argument. Seebeck data confirmed the enhancement in the values of Seebeck coefficient, power factor and electrical conductivity with annealing temperature. The enhancement of thermo power with annealing temperature is due the fact that it degrades the crystal quality which resulted in the generation of secondary phases. These secondary phases are the major contributors of Seebeck coefficient and electrical conductivity.

Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride.

In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate.

Heat Treatment of NiTi Alloys Fabricated Using Laser Powder Bed Fusion (LPBF) from Elementally Blended Powders.

The use of elemental metallic powders and in situ alloying in additive manufacturing (AM) is of industrial relevance as it offers the required flexibility to tailor the batch powder composition. This solution has been applied to the AM manufacturing of nickel-titanium (NiTi) shape memory alloy components. In this work, we show that laser powder bed fusion (LPBF) can be used to create a Ni55.7Ti44.3 alloyed component, but that the chemical composition of the build has a large heterogeneity. To solve this problem three different annealing heat treatments were designed, and the resulting porosity, microstructural homogeneity, and phase formation was investigated. The heat treatments were found to improve the alloy’s chemical and phase homogeneity, but the brittle NiTi2 phase was found to be stabilized by the 0.54 wt.% of oxygen present in all fabricated samples. As a consequence, a Ni2Ti4O phase was formed and was confirmed by transmission electron microscopy (TEM) observation. This study showed that pore formation in in situ alloyed NiTi can be controlled via heat treatment. Moreover, we have shown that the two-step heat treatment is a promising method to homogenise the chemical and phase composition of in situ alloyed NiTi powder fabricated by LPBF.

Selective Hydrogen Absorption by Ti–Ni Powders near Equiatomic Composition after High-Intensity Mechanical Treatment

Selective Hydrogen Absorption by Ti–Ni Powders near Equiatomic Composition after High-Intensity Mechanical Treatment

Sepiolite Fiber Supports Tin Powder and Boron Nitride to Prepare Epoxy Composites with Insulation Properties and High Through-Plane Thermal Conductivity

Metal fillers are not suitable for direct mixing and casting with thermosetting resins to prepare thermally conductive and insulating materials due to their high density and electrical conductivity. Here, we obtain a filter cake by mixing sepiolite fiber, tin powder, and h-BN through vacuum filtration. Low melting point tin particles are melted and allowed to infiltrate to fill the void defects around them after the filter cake is heat-treated, and the added h-BN will coat the tin particles to prevent them from coming into contact with each other to conduct electricity but does not hinder heat conduction. The test results show that when the tin powder content is about 47.2 wt %, the thermal conductivity can reach 3.37 W/m·K and the volume resistance is still greater than 109 Ω·m. This method provides an idea for the preparation of high thermal conductivity metal-thermosetting resin composite materials.

Влияние механической активации порошка вольфрама на структуру и свойства спеченного материала SN-CU-CO-W

Introduction. One of the methods for improving the properties of sintered materials is mechanical activation of powders. It ensures milling the powders, changing its energy state, intensifying the sintering of powder materials, and forming a fine-grained structure in it. When tungsten powders are mechanically activated in planetary centrifugal mills, nanoparticles can be formed, which have a high reactive power. The objective of the paper is to study the effect of mechanical activation of tungsten particles on the structure and properties of the sintered Sn-Cu-Co-W powder material. Research technique: Mechanical activation of W16,5 grade tungsten powder is carried out in a planetary centrifugal ball mill AGO-2U for 5…120 minutes with carrier speeds of 400…1,000 rpm. The mixture of tungsten, tin, copper, and cobalt powders are compacted by static pressing in molds and then sintered in vacuum at 820 °C. The morphology and size of powder particles, as well as the structure of the sintered samples, are studied by scanning electronic microscopy, X-ray microanalysis, and optical metallography. Porosity of the sintered samples is identified by the gravimetric method. Microhardness of the structural constituents and macrohardness of the sintered materials are measured, too. Results: in the modes under study, mechanical activation is accompanied by the formation of tungsten nanoparticles with the minimum size of 25 nm. Alongside this, the powder is exposed to cold working, which hinders further milling. Tungsten nanoparticles, characterized by high surface energy, have a significant effect on the dissolution-precipitation of cobalt during liquid-phase sintering of Sn-Cu-Co-W powder material. Addition of nanodispersed tungsten into the material slows down the growth of cobalt particles during sintering and contributes to the formation of a fine-grained structure. The sintered Sn-Cu-Co-W material, containing mechanically activated tungsten, features higher hardness of 105…107 HRB, which is explained by cold working of tungsten particles and dispersion hardening. The results can be applied for improving mechanical properties of Sn-Cu-Co-W alloys used as metallic binders in diamond abrasive tools.

Synthesis of Multiscale Ultrafine Copper Powder via Radio Frequency Induction Coupled Plasma Treatment

Nano-sized spherical copper powder has important applications in the fields of microelectronic devices, highly efficient catalysts and lubricant additives. In this study, nano-sized and micron-sized spherical copper powders were simultaneously prepared by radio frequency (RF) induction coupled plasma technology. The effects of processing parameters on the powder properties were studied. The results show that by inputting copper powder with D50 = 34.6 μm, nano-sized spherical powder with a particle size of 10–220 nm and micron-sized spherical powder with a particle size of 4.0–144.0 μm were obtained. The ratio of the nano-sized powder reached 86.4 wt.%. The optimal processing parameters are as follows: powder feed rate is 5.5 g/min, carrier gas flow rate is 5–6 L/min and reaction chamber pressure is 15 Psia. When the carrier gas flow rate is 6 L/min, in the plasma zone (>10,000 K), the powder with particle size <42.0 μm is completely vaporized, which forms nano-sized powder during cooling, while the powder with particle size >42.0 μm is melted and partially vaporized, forming a micron-sized powder. The research results provide a new way for engineering the production of copper nano-powder and some other nano-powders with low melting points, such as silver powder, tin powder and so on.

Laser Powder Bed Fusion of Defect-Free NiTi Shape Memory Alloy Parts with Superior Tensile Superelasticity

Laser powder bed fusion is a promising additive manufacturing technique for the fabrication of NiTi shape memory alloy parts with complex geometries that are otherwise difficult to fabricate through traditional processing methods. The technique is particularly attractive for the biomedical applications of NiTi shape memory alloys, such as stents, implants, and dental and surgical devices, where primarily the superelastic effect is exploited. However, few additively manufactured NiTi parts have been reported to exhibit superelasticity under tension in the as-printed condition, without a post-fabrication heat treatment, due to either persistent porosity formation or brittleness from oxidation during printing, or both. In this study, NiTi parts were fabricated using laser powder bed fusion and consistently exhibited room temperature tensile superelasticity up to 6% in the as-printed condition, almost twice the maximum reported value in the literature. This was achieved by eliminating porosity and cracks through the use of optimized processing parameters, carefully tailoring the evaporation of Ni from a Ni-rich NiTi powder feedstock, and controlling the printing chamber oxygen content. Crystallographic texture analysis demonstrated that the as-printed NiTi parts had a strong preferential texture for superelasticity, a factor that needs to be carefully considered when complex shaped parts are to be subjected to combined loadings. Transmission electron microscopy investigations revealed the presence of nano-sized oxide particles and Ni-rich precipitates in the as-printed parts, which play a role in the improved superelasticity by suppressing inelastic accommodation mechanisms for martensitic transformation.

Influence of process parameters on particle characteristics using a combined pressure-swirl-gas atomizer

Abstract This paper summarizes the latest results in the development of a combined pressure-swirl-gas atomizer. The main goals of this investigation are to characterize the generated metal powders in terms of spray pattern and particle size distribution. With the combined pressure-swirl-gas atomizer it is possible to create 150 kg h – 1 of tin powder with mass medians between 30 and 110 μm (tin alloys) and geometric standard deviations below 1.9 with a nitrogen consumption of 100 kg h – 1. Gas flow and melt mass flow can be varied independently of each other, while their characteristic ratio of mass flows can be held below 0.7, which opens new potential for low gas consumption in gas atomization. The experiments were conducted with water and tin melts as model fluids. The comparison of the dimensionless numbers shows that the model experiments are comparable and basically extendable to other melts as long as the material characteristics allow this.

Sinter-swage processing of an Al-Si-Mg-Cu powder metallurgy alloy

ABSTRACT A powder metallurgy (PM) alloy similar to wrought aluminum alloy 6013 was researched. Alloy variants emphasised systems with/without prealloyed manganese and admixed elemental tin powder. Systems with prealloyed manganese demonstrated an inferior response to die compaction and only achieved a density of 91% of theoretical after sintering. Conversely, the mixture that contained a trace addition of tin and was devoid of manganese densified to >98%. In the T6 state, this particular PM variant exhibited stiffness and yield strength that were comparable to wrought 6013-T6 but maintained a limited tensile ductility. The latter trait, as well as UTS and fatigue performance, were all improved significantly with the inclusion of a hot swaging step after sintering. As hot swaging eliminated the bulk of residual porosity in the sintered preform, this was believed to have underpinned much of the gains realised.